My solution is relevant to disabling access to fillable fields in an interactive form. You can fire this script on any event including submission. The problem with this solution is that you would have to control distribution of the form to ensure recipients get the locked version or have a mechanism to recognize the role of the person opening the form.
There are multiple solutions for preventing changes. It depends upon your requirements and the type of changes you are worried about. For example, you could add password security to allow or prevent changes. Another common approach is to flatten a PDF so it is no longer interactive.
Steve